The invention relates to chewing gums containing dipeptide sweetener. The term xe2x80x9cchewing gumsxe2x80x9d as used in this application refers to all forms of chewing gum products and includes the normal chewing gums and the so-called xe2x80x9cbubble gumsxe2x80x9d, both in a sugar-free and in a sugar-containing form. The term xe2x80x9cchewing gumsxe2x80x9d also includes all other forms of chewable products sweetened with dipeptide sweetener, such as chewing tablets based on gum. The invention is intended to improve the flavour of such chewing gums, both insofar as the quality of flavour is concerned and also insofar as the persistence of the flavour is concerned. In particular the invention relates to chewing gum products sweetened with a dipeptide sweetener which contain flavourings based on aldehydes (i.e. the so-called aldehyde flavour products, or aldehyde flavourings). The term xe2x80x9caroma substancesxe2x80x9d is sometimes used instead of xe2x80x9cflavouringsxe2x80x9d.
Chewing gums sweetened with dipeptide sweetener are known and described in various patent publications, for example in WO-90/06689, where it is stated that the perception of flavour when consuming the chewing gum can be lengthened by adding spicy plant extracts (so-called xe2x80x9cspice ingredientsxe2x80x9d). WO-92/07473 describes chewing gums in which longer and improved flavour is achieved by using coated synergistic mixtures of the two intensive sweeteners aspartame and acesulfame-K; it also reports that there are less marked effects as regards stability problems which can arise with aspartame in the presence of aldehydes, ketones, moisture, etc. So-called Maillard reactions, for example, can occur. Such problems of course also affect the stability of the chewing gums during storage, the storage stability.
Chewing gums sweetened with dipeptide sweetener are commercially available, in various flavours, including aldehyde flavour or mint flavour, such as products from the Wrigley range, e.g. Wrigley""s Extra PlenTpak with cinnamon flavour and Wrigley""s Orbit with mint flavour.
For the purposes of this application xe2x80x9cdipeptide sweetenerxe2x80x9d means products with a sweetening power which is many dozens of times stronger than that of sugar, and which are made up of amino acids or derivatives of amino acids linked via a peptide bond. The best-known examples of dipeptide sweeteners are aspartame and alitame.
Aspartame (xcex1-L-aspartyl-L-phenylalaninemethylester), hereinafter also referred to as APM, is a dipeptide sweetener with a sweetening power which is approximately 200xc3x97 that of sucrose. Aspartame is used as an intense sweetener in many applications because of its good flavour properties and low-calorie characteristics. Aspartame is also widely used in chewing gums.
Alitame (L-xcex1-aspartyl-n-(2,2,4,4-tetramethyl-3-thietanyl)-D-alanineamidehydrate), hereinafter also referred to as ALI, is a dipeptide sweetener with a sweetening power which is approximately 2000xc3x97 that of sucrose.
It is also known that dipeptide sweeteners in chewing gums are used in the form of blends, i.e. physical mixtures, with other sweeteners. See for example Patent WO-92/07473, already mentioned above, in which a (coated) blend of APM and acesulfame-K (the potassium salt of 6-methyl-1,2,3-oxathiazin-4(3H)-one-2,2-dioxide, hereinafter also referred to as Ace-K) is used.
As is to some extent already apparent from the foregoing, the use of dipeptide sweeteners in chewing gums etc., in particular in chewing gums which contain flavourings based on aldehydes, is impeded by problems resulting from the somewhat limited chemical stability of the dipeptide sweeteners, in addition to problems with regard to the fact that the release of the sweet taste in the relevant applications (the so-called xe2x80x9csweetness releasexe2x80x9d) is not optimal. WO-92/07473 and EP-A-0457724, for example, state that aspartame shows instability in the presence of aldehydes, ketones, moisture etc. This is already detrimental during the production of the chewing gums, but also detrimental to the storage stability of the products in which the said components are present together, as the sweetening power decreases as a result. Under such circumstances, as a result of unwanted reactions, there may also be discoloration of the (solid) products in which a dipeptide sweetener is incorporated.
In the prior art efforts have been made to find solutions with the aim of lengthening the perception of flavour when consuming chewing gums, and also with the aim of combating stability problems due to the presence of dipeptide sweetener in chewing gums, by for example providing the dipeptide sweetener with a coating, in an extra process step. This is described in EP-A-0461197, for example. As described in EP-A-0160607, for example, attempts have also been made to combat stability problems in chewing gums containing aldehydes, for example, by applying the dipeptide sweetener to the surface of the chewing gum. All this has disadvantages, however, in terms of the complexity of manufacture and requires additional process steps. In addition, so-called xe2x80x9chot spotsxe2x80x9d may occur in chewing gums which are sweetened with coated sweeteners. In order to improve these various aspects, blends of a dipeptide sweetener and another intense sweetener, such as acesulfame-K or saccharin, are therefore also used in chewing gums. When such blends are used, there will usually be different peaks in the perception of the sweetness during consumption of a chewing gum, because of differences in the sweetening profiles of the various sweeteners, and there is also a risk that a bitter or pungent flavour may be perceived at certain periods during consumption. In addition it should be noted that attempts have also been made to influence the profile of the release of sweetening power in chewing gums etc. by varying the particle size of the dipeptide sweetener used in these products (see for example EP-A-0427541), or by appropriate choice of the location of the sweetener in the chewing gum product to be sweetened (e.g. by powdering the outside of chewing gum strips with sweetener or by providing the chewing gum itself with a coating which is also sweetened and optionally contains an aldehyde aroma component, as is described for example in EP-A-0129584).
According to the prior art there is thus still no entirely satisfactory solution for producing a desired sweetness level and sweetening power profile in chewing gumsxe2x80x94in terms inter alia of the intensity, quality and persistence of the sweet taste perceptionxe2x80x94during the consumption time while chewing, and in addition the consumption time is generally found too short. This is especially the case when the chewing gums also have reduced storage stability (i.e. loss of sweetening power during storage).
There is therefore a need to provide chewing gums containing dipeptide sweetener with a lengthened and improved flavour. There is also a need for a method of producing such chewing gums with a lengthened and improved flavour in a simple way. In particular there is a need to improve the flavour quality and the persistence of the flavour of chewing gum products sweetened with a dipeptide sweetener which contain flavourings based on aldehydes.
Surprisingly, extensive research by the applicant has now yielded chewing gums containing dipeptide sweetener with outstanding flavour quality and persistence of flavour, where the dipeptide sweetener is a sweetening salt of an aspartic-acid-derived dipeptide sweetener and a derivative of a sweetening acid. It has been found that chewing gums with such a composition show a surprisingly long duration of the sweetening power during consumption and have very good flavour quality.
In particular it has also been found that chewing gum products sweetened with a dipeptide sweetener which contain flavourings based on aldehydes show a surprisingly long duration of the sweetening power during consumption and have very good flavour quality when the dipeptide sweetener is a sweetening salt of an aspartic-acid-derived dipeptide sweetener and a derivative of a sweetening acid. This is true both when the chewing gums are consumed shortly after their manufacture and when the chewing gums are stored for a long period, e.g. a few months, before being consumed. The storage stability of such products is therefore also considerably better than that of chewing gums sweetened with a (free or mixed) dipeptide sweetener.
Sweetening salts of an aspartic-acid-derived dipeptide sweetener and a derivative of a sweetening acid as meant here are described in CA-A-1027113 and ES-A-8604766, and also in Belgian patent application No. 9500836, which had not been prepublished on the priority date of the present application and which led to inter alia EP-A-0768041. Derivatives of sweetening acids as meant here are (derivatives of) organic acids corresponding to an intense sweetener which is not derived from aspartic acid. From none of the documents mentioned here, in which moreover possibilities of application for the sweetening salts in question are only indicated in very general terms without showing concrete applications, can it be inferred or expected that these sweetening salts in chewing gums have such a strong effect on the duration of the sweetening power during consumption or on flavour quality and stability. This is relevant not only in comparison with chewing gum products in which only a dipeptide sweetener is present as the sweetening component but also in comparison with chewing gum products in which the dipeptide sweetener is used in the form of a blend.
Examples of suitable sweetening salts which according to the invention can be used in chewing gums are: salts of aspartame (APM) or alitame (ALI) with acesulfamic acid (i.e. the acid derived from Ace-K), with saccharic acid (1,2-benz-isothiazol-3(2H)-one-1,1-dioxide) and with cyclohexylsulfamic acid (cyclamate). The most suitable one is the salt of aspartame and acesulfamic acid, hereinafter also referred to as APM-Ace or as the APM-Ace salt; particularly suitable is the exceptionally stable, non-hygroscopic product as obtained in solid form by the method in Belgian non-prepublished patent application No. 9500836. In said method aspartame and a salt of acesulphamic acid are allowed to react in an aqueous medium in the presence of a strong acid, and the APM-Ace formed is isolated from the reaction mixture.
The particle size of the sweetening salts which under this invention are used in the relevant chewing gums, and in particular the particle size of the sweetening salts as present at the time of manufacture of the chewing gums, is not particularly critical, but is generally not more than 500 xcexcm. The presence of larger particles in the chewing gum causes less homogeneous and less balanced release of the sweetening power during consumption. Use of a sweetening salt with a particle size  less than 350 xcexcm offers advantages in terms of the flavour quality of the chewing gum. The best flavour quality is achieved if the particle size of the sweetening salt is in the range  less than 100 xcexcm, but particles in the range 100-200 xcexcm also give products with excellent and lengthened flavour when used in chewing gums. In a number of cases somewhat better stability of the products is also obtained with sweetening salt particles in the range 100-200 xcexcm. By choosing the particle size of the sweetening salt to be used, the specialist can achieve further fine-tuning of the desired flavour quality and stability.
The content of sweetening salt in the chewing gums according to the invention can vary within a very wide range, but it should generally lie within the range from 100 to 6000 ppm (calculated relative to the total mass of the chewing gum).
It will be clear to the specialist that although chewing gums with a lengthened flavour are already produced according to the invention, the flavour profile of the chewing gum products can be further adjusted by adding additional small quantities of a separate intense sweetener or a blend of sweeteners, in addition to choosing the particle size of the sweetening salt. Accelerated emergence of the sweet flavour, the so-called xe2x80x9cup-front releasexe2x80x9d, can thus be achieved, for example. In addition, the flavour profile of the chewing gums can be further influenced by applying all or a proportion of the particles of the sweetening salt in the chewing gum in coated form, or by adding the additional small quantity of a separate intense sweetener (if one is used) to the chewing gum also partially or entirely in coated form. Application of part or all of the sweetener in coated form ensures an adapted profile of the release of the sweet flavour and can thus be regarded as a form of xe2x80x9ccontrolled releasexe2x80x9d. In addition, all the known techniques in relation to the technical shaping of the final product (the chewing gum) and/or the components to be incorporated, such as the sweetening salt, are of course also available to the specialist in order to achieve further desired flavour effects and/or aesthetic effects. Examples of such techniques in relation to the technical shaping of the components are granulation, grinding, freeze-drying, spray-drying, agglomeration etc. The invention is in no way limited with regard to the place where the sweetening salt used according to the invention is located in or on the chewing gum.
As is known and customary, chewing gums consist in large part (about 5 to 95% by wt) of a so-called xe2x80x9cgum basexe2x80x9d and all sorts of additives, such as aroma substances. The gum base generally consists of a combination of natural gums and/or synthetic elastomers and resins, and also contains softeners and (5 to 60% by wt) inorganic fillers. The gum base may also contain other components such as antioxidants, colorants and emulsifiers. Within the framework of the present invention the kind and nature of the components of the gum base is not critical, but it is self-evident that if aldehydes, ketones etc. are present in the gum base, there may be a detrimental effect on the properties of chewing gums which contain APM, for example, as sweetener. Furthermore, the chewing gums contain all sorts of flavourings which may originate from natural plant extracts or be obtained synthetically.
Examples of aldehyde flavourings which can be used in chewing gums are acetaldehyde, benzaldehyde, anisaldehyde, cinnamaldehyde, citral, xcex1-citral, xcex2-citral, decanal, ethyl vanillin, heliotropin (piperonal), vanillin, xcex1-amyl-cinnamaldehyde, citronellal, aldehyde C-8, aldehyde C-9, aldehyde C-12, trans-2-hexenal, veratraldehyde, etc.
Examples of ketones which can be used in chewing gum products are acetophenone, acetone, methyl-n-amylketone, p-hydroxyphenyl-2-butanone, xcex1-ionone, xcex2-ionone, methyl-3-butanone, 2-heptanone, o-hydroxy-acetophenone, 2-methyl-2-hepten-6-one, 2-octanone, 2-undecanone and 2-pentanone.
Besides the sweetening salts to be used according to the invention, food sugars and/or other sweeteners can also be present in the chewing gums according to the invention. Examples of these are aspartame, alitame, acesulfame-K, saccharinates, cyclamates, glycyrrhizin, thaumatin, monellin, neohesperidin dihydrochalcone (abbreviated to NHDC), sucralose, sorbitol, mannitol, xylitol, hydrogenated starch hydrolysates, dextrins, maltitol, sucrose, dextrose, glucose syrups, fructose, fructose syrups, etc., or combinations thereof.